|TAAL VOLCANO Advisory, 30 May 2011, 8:00 A.M.|
|Monday, 30 May 2011 06:15|
This is a notice of a remarkable increase in the seismic activity of Taal Volcano.
For the past 24 hours, Taal‘s seismic network detected a total of one hundred fifteen (115) volcanic earthquakes . Twelve of these events were felt at Intensity I – IV by residents of Pira-piraso, Alas-as and Calauit located at northeast, southwest and southeast sectors of Volcano Island, respectively. One of these events (8:32 PM, 29 May) was felt at Intensity I, nine (9) events (1:02:19 AM, 1:02:26 AM, 2:32 AM, 2:53 AM, 2:12 AM, 3:08:19 AM, 3:08:52 AM, 3:17 AM, 3:19 AM, 3:26 AM 30 May) were felt at Intensity II, one event (1:26 AM 30 May) was felt at Intensity III and another one (1:05 AM 30 May) was felt at Intensity IV. All of these felt events were reportedly accompanied by rumbling sounds.
Field measurements conducted on 24 May 2011 at the eastern sector inside the Main Crater Lake showed that the water temperature slightly increased from 32.5°C to 32.8°C, and the pH value became more acidic decreasing from 2.83 to 2.67. Results of the ground deformation survey (precise leveling) conducted around the Volcano Island last 26 April - 03 May 2011 showed that the volcano edifice inflated slightly relative to the 05-11 April 2011 survey. Measurement of carbon dioxide (CO2) gas emission rates last 03-04 May 2011 at Taal Main Crater Lake yielded a value of 2,057 tonnes per day (t/d) which is twice the background level.
In view of the above observations, PHIVOLCS reiterates Alert Level 2 over Taal Volcano. This means that magma has been intruding towards the surface, as indicated by the continuing high level of seismic activity and sustained high emission rate of CO2 being released in the Main Crater Lake. PHIVOLCS advises the public that the Main Crater, Daang Kastila Trail and Mt. Tabaro (1965-1977 Eruption Site) are strictly off-limits because sudden hazardous steam-driven explosions may occur and high concentrations of toxic gases may accumulate. Breathing air with high concentration of toxic gases can be lethal to human, animals and even cause damage to vegetation. In addition, it is reminded that the entire Volcano Island is a Permanent Danger Zone (PDZ), and permanent settlement in the island is strictly not recommended. DOST-PHIVOLCS is closely monitoring Taal Volcano’s activity and any new significant development will be immediately relayed to all concerned.